1. Field
Exemplary embodiments of the present invention relate to a method of fabricating a semiconductor device, and more particularly, to a back side illumination image sensor and a method for fabricating the same.
2. Description of the Related Art
An image sensor is a device that converts an optical image into an electric signal. The image sensor is generally classified into a charge coupled device type (CCD type) image sensor and a complementary metal oxide semiconductor type (CMOS type) image sensor. The image sensor includes a plurality of pixels, and each pixel outputs a pixel signal corresponding to incident light. Each pixel accumulates photocharges corresponding to the incident light through a photoelectric conversion device, i.e., a photo diode, and outputs the pixel signal based on the accumulated photocharges.
In the image sensor, dark current is generated due to the electric charges generated at the surface of the substrate where the photoelectric conversion device is formed. The dark current degrades the properties of the image sensor by acting as noise to the pixel signal.